Manufacture of rennet



i urrso s'rA'rs Patented June 20, 1944 s FATE assess: V

M mxuracruaaormne'r Basil Dnperler Thornley and display. Hilton,Wilmslow, England, aesignors toBengers Limited, Holmes Chap Cheshire,England No Drawing. Application March 26, 1941,8erial No. 385,306. a InGreatBrttsinMa-rch 28, 1940 18 Claims. (c1. res-c3) "1 This inventionrelates to improvements in the manufacture of rennet for use incoagulatin milk and particularly to improvements in solidrennetpreparations in the form of powderor tablets." l

According to our invention of rennet or containing rennet, such as forinstance is produced by salting out an extract of the enzyme, is mixedwith a suitable efilorescent salt which probably acts ass waterexchanger whereby water is. passed into the atmosphere by hydrationrollowed by tie-hydration or the salt In thisway a dry product adaptedfor tablet making is obtained. An efllorescent salt can be consideredsuitable if it'will not appreciably impair the activity of the rennetunder the conditions of use and prooi' course it has no poisonous orother properties which would render the preparation .unilt for useinconnection with foodstufis. It

a moist preparation must also be efiorescent under conditions "of tenipperature, pressure and humidity which will not damage the rennet.Accordingly vacuum drying with or without a desiccating agentor dryingby application of warmth may be used on a mixture according to theinvention. A Itis to be observed in connection with. thiscriterion ofsuitability that almost any salt forming definite hydrates'can be madeto eliioresce if the pressure is reduced to a sumciently low level andthe temliterature raised sumciently high, that is,when

the vapor pre ssure of the surrounding atmosphere is reducedsuificiently below that or the particular hydrate. However, only salts,otherwise suitable, i'orming hydrates with a relatively high vaporpressure can be consideredas prac- "tlcally useful water exchangers forthe purpose of the invention even when assisted by vacuum Two or moresuitable efilorescent salts may be fused together providing they do notreact together undesirably.

.Thejeiliorescent saltvneed not necessarily be used injanhydrouscondition or lower state of hydration f although this is generallypreferable since dryingis then quicke Our investigations indicate thatsodium sulphate is the. most satisfactory drying agent to the moistpreparation with the sodium sulphate. However in intimateadmixture theresulting dry preparations, when treated with water, are liable to showlocal alkaliniiyin the neighborhood of the phosphate particles with thedanger of subsequent damage to the rennet on this account.

'When dipotassium hydrogenphcsphate is used to give optimum drying,therefore, the dried rennet powder should be dissolved before use in, a.slightly acid or neutral louder solution or added direct to the milksince this itself sufiicient buffering properties to prevent shift ofpH. The

optimum increase in drying effect appears to be obtained when thedipotassiuin phosphate isadded insufiicientquantity to adjust the pH toabout 7.0.

mother salt which. can he used according to the invention is magnesiumsulphate. The ex- "acidity of the wet preparation must "he sufiicient topermit enough of this salt to be addedto bring about drying withoutraising the pHof the mixture sufficiently above 7.0 to damage therennet. Disodium hydrogen phosphate when fully hydrated contains 12molecules of water of crystallization and is efiiorescentat roomtemperatures.

when sodium sulphate is used as drying agent according tothe inventionthe pH of the preparation may be adjusted to about 7.0 either before orafter drying, thatis before'or efter the addition or the 'efiorescentsalt, in order to improve 3 its solubility. We prefer to use dipotassiumor mix according to the present invention with the i moist rennetpreparation and we prefer to use this salt in its anhydrous state.

1 Dipotassium hydrogen phosphate may be added as 'well as the sodiumsulphate to improve the drying efiect still further and such additionthey be made either before or after the admixture 01 disodium hydrogenphosphate forthe purpose of neutralizing an acid preparation but only inthe case already described when dipotasslum hydrogen phosphate is usedin conjunction with sodium sulphate have we been able to observe any-innprovement in the drying effect due to such addition of alkali. Theprecautions already indicated to avoid the development of localalkalinity when dipotassium... hydrogen phosphate and sodium sulphateare used together'and the dry preparation containing them is.sulwequently moistened should also be adopted whenever-alkali is added 7fsince locai amanmt isimble.'tq-destr6y us or process. The'11se:ofalkali.or"alkali salt in con g "M 2 U V to improvethe solubilitya breparationdried tram le; Die 0! fulli hfldr'atd sodium-f by means ofsodium sulphate, the danger being, 'Phate conjunctioniwith dipotqssmm hygreater whenialkalis other than dipotassium or m Phosphate 1 y jdisodium' hydrogen phosphat arei emplo'yed Y I r H a For a' Similarreason such alkalis are prefe' g: 5 3:5:bg fuxf gaiggggggflg g ggg i notadded until the vpreparation has been the rennet whilst'stil1 moistduring the mixing junction withfmagnesinm sulphate serves no 11.ful-purpose since'insoluble residues 'are"pr 'd when the drypreparation is dissolved The present invention, 'fiihich relate so i thedrying ofworkedup rennet preparations r n I fractions, is to bedistinguished from the 'proc i set forth in British PatentSpecificationNoPIBB,

660, which. is concerned .withthei specialproble' of producing a drypowder from pancreas glands either fresh or salted, bygrinding up theactual glands with "aimixture 1 containing anhydrous -s o-'dium-zjsulfate; anhydrous magnesium-sulphate or anhydroussodium-phosphate together with other essential salts'toproduce almostimmediatefiry- 1 ins: 'of-the glandular material. a 'rThetollowingexperimentaldata serves to i trate practical details of theinventionby way I grAfterdrying'eflioreseence gradually took, placeg-;"I'his was facilitated bycrnshing the hard eakeg 92 hgrams of the Jdrysolid, before complete emorescence' had taken place; was obtainecontainingythewhole ot -the original rennet y."

"page; of qnhjidroda ,sodfilmsu phate in;i coniuncti on:wtthqdipotassimn hydrogen 39 g ins er 'ajnnydmus sodium s lp ate? 1 9gramsfof dipota'ssium hydrogen phosphate f 3.6;'k-fThemixturedriedinltwodays et ro0m-teni-' l perature. 8.5 gra'ms'of the resulting dry. :soli

inal rennet activit 8. The process as defined in claim 7 wherein itwater present in the mixture until the residue the salt is added in aquantity approximately thereof reaches a predetermined degree of dry- 7equal to the weight of the material to be dried. ness.

" 7 9. "The process defined in claim Twhe'rein' the 15. A milk coagulantin the form of a powder, transpiration or water is eflected in a vacuum.comprising rennin-containing material derived 10..Ihe process defined inclaim! wherein the 20 from remote, said material having an initial pHtranspiration of water is accelerated by applybelow about 3.6, inadmixture with anhydrous ing heatto raise the mixture to a temperaturesodium sulphate and a, monohydrogen phosphate notin excess of about 38C. 01' an alkali metal, said anhydrous sodium sul- 11. The processdefined in claim '7 wherein the phate and said phosphate formingtogether a transpiration or water is eilected in a vacuum 2.) majorfraction or said powder, and said phosand at an elevated temperature notexceeding phate being present in said powder in quantity about 38' C.sumcient to raise the pH of said rennin-contain- 12. A milk coagulant inthe form of a powder, ing material, but insufficient to raise said pHcomprising rennin-containing material derived substantially above 7.0.from rennets, said material having an initial an 16. A milk coagulant inthe form of a powder,

com

assaosr taining material derived from rennets, said maierial having aninitial pH below about 3.6, which comprises, mixing with said material asalt capable of elilorescence, selected from the group consisting ofsodium sulphate and magnesium sulphate, and permitting transpirationinto the vapor state of water present in the mixture until the residuethereof reaches a predetermined degree of dryness.

pH below about 3.6, in admixture with sodium sulphate and a monohydrogenphosphate of an alkali metal, said sodium sulphate and said phosphateforming together a major fraction of said powder, and said phosphatebeing present in i said powder in quantity sufiicient to raise the pH ofsaid rennin-containing material, but insufilcient to raise said pHsubstantially above 7.0.

13. A milk coagulant in the form of a powder prising rennin-containingmaterial derived from rennets. said material having an initial pl! belowabout 3.6, in admixture with saline material capable of eiilorescence,and selected from the group consisting of sodium sulphate and magnesiumsulphate, said saline material forming a major fraction or said powder.

14, The process of drying moist rennin-containing material derived from'rennets, said material having an initial pH below about 3.6, whichcomprises, mixing with said material a monohvdrogen phosphate of analkali metal in amount sufiicient to increase the pH of the mixture, butinsufiicient to raise the pH substantially above 7.0. and anhydroussodium sulphate, and permitting transpiration into the vapor state 0!comprising rennin-containing material derived from rennets, saidmaterial having an initial pH below about 3.6, in admixture with salinematerial capable of hydration, said saline material being selected fromthe group consisting of an- CERTIFICATE OF CORRECTION.

.Patent No. 2,552,057.

June 20 19bit.

BASIL DUPERIER THORNIEY, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,first column, line 51, before the word "was" insert --now'Patent No.2,557,9lfl issued December 28, 1914.5"; and that the said Letters Patentshouldbe read with this correction therein that the same may conform tothe record of the case in the Patent Office.

Signed and sealed this 5th day-of September, A. D. 19%.

Leslie Frazer Acting Connnissioner of Patents.

(Seal) CERTIFICATE OF CORRECTION. Patent No. 2,552,0 7. June 20, 19M.

BASIL DUPERIER THORNLEY, ET AL.

column, line 31, before the word "was" insert --now Patent No.2,557,9LL7 issued December 28, 19145"; and that the said Letters Patentshould be read with this correction therein that the same may conform tothe record of the case in the Patent Office.

Signed and sealed this 5th day of September, A. D. 191411..

Leslie Frazer (Seal) Acting Commissioner of Patents.

